A cluster communication system is a dedicated wireless communication system which is developed to meet command and dispatch requirements of industry users and is applied to a specific industry. A great number of wireless users in the system share a small number of wireless channels. The cluster communication system is a multipurpose and highly-efficient wireless communication system which is mainly applied to command and dispatch. The cluster communication system has the special characteristics of dispatch, group calling, quick calling and the like, and has become a development direction of a next generation cluster system.
A Long Term Evolution (LTE) cluster communication system realizes various requirements and functions of a cluster by extension on the basis of an LTE system. In terms of a networking architecture, an Electronic Product Code (EPC) of an LTE core network and a Decision Support System (DSS) of a cluster core network achieve complete isolation of services and networking of cluster applications, do not depend on a conventional LTE EPC device, do not affect normal running of a conventional LTE EPC core network device, and can isolate a private network and share a public network.
A user is attracted by a cluster service due to a rapid contact way, and therefore the performance of the cluster service is a key factor which decides whether the cluster service can operate successfully. A first index in the performance of the cluster service is voice intelligibility and a data receiving rate. In order to ensure the voice intelligibility and the data receiving rate, a cluster terminal is needed to reside in a better cell. In order to achieve this, the cluster terminal is enabled to timely measure a better adjacent cell and to switch to the cell, thereby making the cluster terminal always reside in a better cell to use voice and data services, and ensuring the quality of the services. However, a problem urgently needed to be solved is how to enable the cluster terminal to timely measure the better adjacent cell and to switch to the cell so as to make the cluster terminal always reside in the better cell to use the voice and data services.